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Alameda County · Building on your lot

Building on your lot in Alameda County

Alameda County's code applies only in unincorporated areas of the county. It sets fence heights by yard and corner location, limits detached accessory buildings in R districts, and lists businesses not allowed as home occupations.

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Key points

  • Fence height: County fence limits: 4 feet in required front yards, 2 feet near corner-lot intersections, 6 feet elsewhere in A or R districts.
  • Accessory buildings: In R districts, the county limits detached accessory buildings to one story and 15 feet, at least 6 feet from other buildings.
  • Home business: County home occupations may use at most 1/4 of the dwelling unit; barber shops, beauty shops, real estate offices and massage are not allowed.

Each rule below is marked Alameda County code or CA state law and links to the section it comes from (checked October 2026). General information, not legal advice.

Alameda County's code applies in the unincorporated areas of the county. Cities in Alameda County have their own codes and their own pages.

Fences and walls

Alameda County code What Alameda County's code adds
Corner visibility
  • No more than 2 feet tall, measured up from the center line grade of the street opposite.
    Applies: In a required yard on a corner lot, within 30 feet of where the street lot lines, or their extensions, meet.
    § 17.52.430 · code text
    When located in a required yard on a corner lot and within thirty (30) feet of the intersection of the street lot lines or of the projections of such lines: Two feet, measured upward from the center line grade of the street opposite thereto;
Height anywhere on the lot
  • No more than 6 feet tall.
    Applies: In A or R districts, outside the required front yard and the corner lot areas that have lower limits.
    § 17.52.430 · code text
    When located in any A or R district other than as specified hereinabove six feet;
  • Open wire fences can be up to 6 feet tall.
    Applies: Only open wire fences in an A district; the yard height limits do not apply to them.
    § 17.52.440 · code text
    An open wire fence up to six feet high in an A district.
Front yard height
  • No more than 4 feet tall.
    Applies: In a required front yard, except within 30 feet of the street corner on a corner lot, where the limit is 2 feet.
    § 17.52.430 · code text
    When located in a required front yard other than as specified in subsection A of this section: Four feet;
Side and rear yard height
  • No more than 4 feet tall.
    Applies: Required rear or street side yard of a corner lot, within 20 feet of the corner shared with a key lot behind it.
    § 17.52.430 · code text
    When located in a required rear or street side yard of a corner lot and within twenty (20) feet of the corner common to such a lot and a key lot at the rear: Four feet;

Sheds, garages and other accessory structures

Alameda County code What Alameda County's code adds
Maximum height
  • No more than 1 story and no taller than 15 feet.
    Applies: Detached accessory buildings in an R district.
    § 17.52.260 · code text
    No detached accessory building in an R district shall be located within six feet of any other building on the same lot, or have more than one story or a height in excess of fifteen (15) feet.
Side and rear setback
  • At least 6 feet from the side line of the front half of a neighboring lot.
    Applies: Accessory buildings in an R district.
    § 17.52.270 · code text
    No accessory building in any R district shall be within six feet of the side line of the front half of any abutting lot, or occupy the front half of a lot, or either front quarter of an interior lot abutting two streets, provided; however, that this restriction shall not require any accessory building to be more than seventy-five (75) feet distant from any street lot line.
  • At least 10 feet from the side lot line, and no closer to the street side line than the house.
    Applies: Corner lots in an R district whose rear lot line borders the rear lot line of another lot.
    § 17.52.280 · code text
    Where the rear lot line of a corner lot in an R district abuts the rear lot line of another lot, no accessory building shall be nearer the street side lot line than the main building or in any case be located less than ten feet from the side lot line.
Distance from the house
  • At least 6 feet from any other building on the same lot.
    Applies: Detached accessory buildings in an R district.
    § 17.52.260 · code text
    No detached accessory building in an R district shall be located within six feet of any other building on the same lot, or have more than one story or a height in excess of fifteen (15) feet.

Running a business from home

Alameda County code What Alameda County's code adds
Space used
  • The business can use no more than one-fourth of the home's floor area in total.
    Applies: Home occupations in any R or A district.
    § 17.52.210 · code text
    Any use of the front yard or side yard for construction or repair or dismantling or the use in the aggregate of an area greater than one-fourth of the area of the dwelling unit;
Employees
  • No outside help in the home or on the property, except domestic servants.
    Applies: Home occupations in any R or A district.
    § 17.52.210 · code text
    The employment of outside help in the dwelling or on the premises, other than domestic servants;
Businesses not allowed
  • maintenance on the premises for sale or rental of any stock of goods which are not homemade
    Applies: home occupations in any R or A district
    § 17.52.210 · code text
    Maintenance on the premises for sale or rental of any stock of goods, which are not homemade;
  • massage establishment
    Applies: home occupations in any R or A district
    § 17.52.210 · code text
    The conduct of: a) massage establishment, b) barber shop, c) beauty shop, or d) real estate office;
  • barber shop
    Applies: home occupations in any R or A district
    § 17.52.210 · code text
    The conduct of: a) massage establishment, b) barber shop, c) beauty shop, or d) real estate office;
  • beauty shop
    Applies: home occupations in any R or A district
    § 17.52.210 · code text
    The conduct of: a) massage establishment, b) barber shop, c) beauty shop, or d) real estate office;
  • real estate office
    Applies: home occupations in any R or A district
    § 17.52.210 · code text
    The conduct of: a) massage establishment, b) barber shop, c) beauty shop, or d) real estate office;
  • raising animals, bees or birds for sale
    Applies: home occupations in any R or A district
    § 17.52.210 · code text
    The raising for sale of animals, bees or birds; or
  • teaching dancing, music or swimming to an assembled class of more than two pupils
    Applies: home occupations in any R or A district
    § 17.52.210 · code text
    The teaching of dancing, music or swimming to an assembled class of more than two pupils;
  • repair, servicing, painting or dismantling of motor vehicles or household appliances
    Applies: home occupations in any R or A district
    § 17.52.210 · code text
    The repair, servicing, painting or dismantling of motor vehicles or of electrical refrigerators, washers, dryers, or other household appliances;
  • renting rooms and providing table board for more than four persons (more than five persons if licensed by the State Department of Mental Health)
    Applies: home occupations in any R or A district
    § 17.52.210 · code text
    The renting of rooms and the providing of table board for more than four persons, or if licensed by the State Department of Mental Health for more than five persons;
  • day care for more than six children
    Applies: home occupations in any R or A district
    § 17.52.210 · code text
    The provision of day care for more than six children.

Other Alameda County rules on this

Alameda County's code also has these chapters. We have not summarized their values on this page yet; read them in the library.

Who this affects

HomeownersContractorsDesigners

Frequently asked questions

How tall can a fence be in Alameda County?

County fence limits: 4 feet in required front yards, 2 feet near corner-lot intersections, 6 feet elsewhere in A or R districts.

How big can a shed or accessory building be in Alameda County?

In R districts, the county limits detached accessory buildings to one story and 15 feet, at least 6 feet from other buildings.

Can I run a business from my home in Alameda County?

County home occupations may use at most 1/4 of the dwelling unit; barber shops, beauty shops, real estate offices and massage are not allowed.

General information, not legal advice.

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Alameda County Municipal Code — full text

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